Vermiculite

C₁₂H₂Al_1.43Fe_0.48Mg_2.37N₂O₁₆Si_2.72

Kanamaru, F.Vand, V.

American Mineralogist (1970) 55, 1550-1561

a=5.33Å   b=9.18Å   c=17.45Å

α=90°   β=97.0°   γ=90°